A TRICH UM UND ULA TUM. 93 



d. The cells of the main part of the lamina with their 

 contents. 



e. The marginal cells, produced into 



/. The sharp forward-pointing teeth, which are often 

 in pairs : observe the distribution of the teeth 

 along the margin, also similar teeth on the under 

 side of the leaf along the summits of the undula- 

 tions and on a part of the midrib. 



g. The surface of the midrib : observe the shape of 

 the cells on the under side ; the rows of chlorophyll 

 tissue on the upper side, which begin near the base 

 of the leaf and extend nearly to the apex, seen as 

 plates in the transverse section. 

 Under high power, notice 



//. The elongated marginal cells, and the shorter cells 

 forming the teeth. 



/. Draw a portion from near the middle of the leaf, 

 showing teeth, marginal cells and some adjacent 

 laminal cells. 



E. THE FLOWERING HEAD. Remove the disk from 

 a male head, and mount, well separated ; notice 



1. Numerous hairs, \hzparaphyses. 



a. The walls, cross partitions, and contents. 



b. Draw. 



2. The antheridium. 



a. The shape. 



b. The elongated cells of the body. 



c. The short cells of the pedicel. 



d. The large apical cell, in antheridia which have not 

 yet burst. 



e. Draw. 



3. The antherozoids. If from a fresh specimen, notice 



